Diazotype materials

ABSTRACT

A diazotype material for use in making copies of X-ray films which comprises a support carrying a light-sensitive layer containing at least one diazonium compound, a coupler and a nonlight-sensitive ultra-violet absorber, the ultra-violet absorber being effective in screening out radiation in the range of 3,400 to 4,000 A, being transparent to all radiation at or above 4,300 A and being present in an amount such as to give a background absorbance of at least 0.9 at 4,000 A.

I United States Patent [151 3,661,591 Reed [45] May 9, 1972 4] DIAZOTYPE MATERIALS 1 f ren Ci ed [72] lnventor: Peter William Maurice Reed, Hockley, En- UNITED STATES PATENTS gland 3,525,618 8/1970 Keller et al. ..96/75 {73] Assigneei on Company Limited, Loughon 2,378,583 6/1945 Schmidt ..96/9l England Primary Examiner-Norman G. Torchin [22] Filed: Mar. 24, 1970 Assistant Examiner-John L. Goodrow Appl. No.: 22,391

US. Cl ..96/91, 96/75 Field of Search ..96/9 1 75 Attorney-Cushman, Darby & Cushman [5 7] ABSTRACT A diazotype material for use in making copies of X-ray films which comprises a support carrying a light-sensitive layer containing at least one diazonium compound, a coupler and a non-light-sensitive ultra-violet absorber, the ultra-violet absorber being effective in screening out radiation in the range of 3,400 to 4,000 A, being transparent to all radiation at or above 4,300 A and being present in an amount such as to give a background absorbance of at least 0.9 at 4,000 A.

4 Claims, No Drawings DIAZOTYPE MATERIALS It is highly desirable to provide duplicates of silver type X- ray films for the use of those who have to attend the patient and it is essential that such duplicates should show hair line cracks and other fine detail in the original. Hitherto it has only been possible to obtain acceptable duplicates by silver photography and duplicates made in this way are expensive.

Diazotype materials are primarily used for making copies of documents and for such use the primary requirement is high contrast between the bleached and colored areas of the copy. it is possible, however, to obtain some degree of tonal gradation in diazotype copies by inclusion in the light-sensitive layer of a plurality of diazonium compounds having overlapping absorption curves for the radiation to which the material is exposed when making a copy.

The present invention is based upon the discovery that it is possible to produce copies of X-ray films acceptable to the medical profession by using a two-component diazotype material which comprises a support carrying a light-sensitive layer containing at least one diazonium compound, a coupler and a non-light sensitive ultra-violet absorber, the ultra-violet absorber being effective in screening out radiation in the range of 3,400 to 4,000 A, being transparent to all radiation at or above 4,300 A and being present in an amount such as to give a background absorbance of at least 0.9 at 4,000 A.

A two component diazotype material for use in making from microfilms copies from which further copies can be made has been proposed in British Specification No. 1094374. This material contains an ultra-violet absorber which is effective in screening out radiation having a wave length in the range of 3,400 3,900 A, is transparent to radiation of wave length at and above 4,000 A, and is present in an amount giving a maximum background absorbance of 0.6 at 4,000 A.

Experiment has shown that this material produces copies of X-ray photographs which are wholly unacceptable since the required fine detail is totally invisible. The material according to the invention, on the other hand, produces copies which are unsuitable for generating further copies because of the high background absorbance.

One U.V. absorber which can be utilized in the diazotype material according to the invention is 7-diethylamino-4- methyl-coumarin which is on sale as an optical whitening agent under the Registered Trade Mark Coumalux. Diazotype material containing this U.V. absorber and with the lightsensitive layer supported on a transparent film backing has been found to have, in the bleached and developed condition, an absorbance of 1.52 at 3,400 A, a peak absorbance of 1.9 at 3,720 A, an absorbance of 1.18 at 4,000 A, an absorbance of 0.08 at 4,300 A and an absorbance of0.06 at 4,400 A.

Another example of U.V. absorber which can be used is the coumarin derivative sold by ClBA under the Trade Mark U- VlTEX SWR." Diazotype material containing this U.V. absorber in its light-sensitive layer has, in the bleached and developed condition, an absorbance considerably in excess of 2 in the range 3,400-4,000 A, an absorbance of 0.2 at 4,300 A and an absorbance of 0. 16 at 4,400 A.

If desired, the light-sensitive layer of the diazotype material according to the invention may be transparent to radiation of wavelength 4,400 A or more. It will normally include in its light-sensitive layer two or more diazonium compounds having overlapping absorption curves. Preferably the background absorbance of the light-sensitive layer does not exceed 2.0.

The support may normally be a transparent film of, for example, a polyester, such as Melinex (Registered Trade Mark) or cellulose acetate because the medical profession prefers to examine X-ray photographs as transparencies. Adequate copies of X-ray films can, however, be produced on diazotype material having a paper support.

The support may, if desired, be pre-treated to facilitate adhesion of the light-sensitive layer. It may also be given a coating of lacquer before application of the light-sensitive layer. Alternatively lacquer may be incorporated in the light-sensitive layer.

Examples of suitable lacquers are cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, polyvinyl acetate and polyvinyl formal. Fillers, such as finely divided silica, may be added to the lacquer.

Examples of suitable compounds which may be employed are:

p-diethylamino-2-ethoxybenzenediazonium fluoroborate;

2,5-diethoxy-4-morpholinobenzenediazonium fluoroborate;

p-diethylaminobenzenediazonium fluoroborate;

1-diazo-4-(N-hydroxyethyl-N-ethylamino )-benzene fluoroborate;

l-diazo-2-ethoxy-4-(N,N-diethylamino)-benzene fluoroborate;

1,diazo-2,5-dimethoxy-4-morpholino-benzene fluoroborate;

l-diazo-4-( N,N-dimethylamino )-benzene fluoroborate;

l-diazo-3-methyl-4-ethylamino-benzene fluoroborate;

l-diazo-2,5-diethoxy-4-morpholino-benzene fluoroborate and l-diazo-4-(N,N-diethylamino)-benzene fluoroborate Examples of suitable couplers are: 2,3-naphthalenediol; naphthalene 2,3-dihydroxy-6-sulphinic acid; resorcinol; 4,4'-diresorcinol, acetoacetanilide; acetoacet-o-toluidide; chlororesorcinol; N,N-bis-B-hydroxyethyl-2-hydroxy-3-naphthoamide; N-( 2 '-methylphenyl )-2- hydroxy-3-naphthoamide; N-y-morpholino-n-propyl-Z- hydroxy-3-naphthoamide and N,N-bis-B-hydroxyethyl-2- hydroxy-3-naphthoamide.

The invention will be further illustrated with reference to the following examples:

EXAMPLE 1 A polyester film (Melinex S Grade) of 0.003 inch thickness was treated with trichloroacetic acid and silica and was then coated with a lacquer which consisted of:

9% second viscosity Cellulose Acetate Butyrate 20.25 g Polyvinyl Acetate/Polyvinyl Alcohol copolymer dissolved in a mixture of: 1.08 g Toluol 49.16 ml 74 overproof Industrial Methylated Spirit 1 1.4 ml Acetone 39.0 ml

together with 0.8 grams of finely divided silica (average particle size l0,u.).

The lacquer was coated on the polyester film and then dried at approximately C. The coating thickness of the dried lacquer was approximately 0.0003 inch.

The lacquered film was then coated with a layer of light-sensitive material which consisted of:

Tartaric Acid 2.0 g Resorcinol 0.3 g N-(2-methylphenyl)-2-hydroxy-3-naphthoamide 0.4 g N,N-bis-fi-hydroxyethyl-2-hydroxy-3-naphthoamide 0.5 g l-diazo-4-(N,N-diethylamino)-benzene flororate 0.6 g l-diazo-2-ethoxy-4-(N,N-diethylamino) benzene fluoroborate 0.6 g l-diazo-2,5-diethoxy-4-morpholino benzene fluoroborate 0.3 g Coumalux" 1.2 g dissolved in:

Methyl ethyl ketone 50 ml 74 overproof Industrial Methylated Spirit 50 ml and then dried at about 1 10 C. The coating weight of the sensitizer was adjusted to give a maximum optical transmission density of 1.5. The background absorbance of the material was approximately 1.06.

This diazotype material gives good reproduction of X-ray films of the silver type.

EXAMPLE 2 The procedure of Example l was repeated except that an equivalent amount of cellulose acetate propionate was utilised in the lacquer in place of the cellulose acetate butyrate.

The background absorbance of the diazotype material was 1-diazo-4-(N,N-dimethylamino)-benzene i l 1 ()6 fluoroborate borate 0.6 appto y ldiazo-3-methyl-4-ethylamino-benzene fluoroborate EXAMPLE 3 l-diazo-2,5-diethoxy-4-morpholino-benzene The lacquer and the sensitizer set out in Example 1 were 5 lfgafig 3:3: mixed together in the ratio of l l by volume and coated on the polyester film. After drying at approximately 120 C.,'the coating had a thickness of approximately 0.0003 inch. The EXAMPLE9 background absorbance was greater than 0.9. l

EXAMPLES 4 6 Methyl ethyl Ketone 50.5 mls ldt'lMthltdS"t 50.0! The procedure set out in Examples 1 to 3 were repeated ZQ'ZJLZJ y a e pm 2.0 a s with the ucou l eplaced by the ultra-violet absorbing fiefgrcinoll I h I) 2 h d 3 hm d 8.3 g u -met yp eny y roxy- -nap oami e .4g composition sold by CIBA under the Trade Mark UVITEX l N,N bis p hydmxyethyl LhYdwwJmaPhthoamide 0.5 g l-diazo-4-(N,N-diethylamino)-benzene Good copies of X-ray films of the silver type were again obfluoroborate 0.6 g mined l diazo-2-ethoxy-4-(N,N-diethylamino)-benzene fluoroborate 0.6 g In the followmg ff j P 1 repeated l-diazo-2,5-diethoxy-4-morpholino-benzene using the following llght-sensitive compositions dissolved in fluoroborate 0.3 g the above stated solvent mixture: Cwmalux 8 EXAMPLE 7 What I claim as my invention and desire to secure by Letters Patent is: Tartaric acid 2.0 g l. A diazotype copying material for use in making Resorl'aclnolh d h 2 h 3 8 duplicates of silver halide X-ray films, said material compris- 'sg 'g i gg ydmxy' 0 4 8 ing a support and, carried upon said support, a light-sensitive N-(2'-methylphenyl)-2-hydroxy-3-naphthoamide 0.5 g layer: comammg hree dlazomum .compounds .havmg y? l diazo 4 (N hydmxyethypwethylamino) benzene lapping absorption curves a coupler and a nonlight sensitive fluoroborate 0.6 g ultra-vlolet absorber consisting essentially of 7-diethylaminoyy y y 4-methyl coumarin, said light-sensitive layer having a bFnzemi ""P 5 background absorbance of at least 0.9 at 4,000 A. l-diazo-2,5-drmethoxy-4-morpholino-benzene fluombome 03 g 2. A diazotype copying material as claimed 1n claim 1, "Coumalux 1,2 g wherein the background absorbance at 4,000 A of the lightsensitive layer does not exceed 2.0.

3. A diazotype copying material as claimed in claim 1, EXAMPLE 8 wherein the support is a transparent film.

4. A copying material as claimed in claim 1, wherein the 40 diazonium compounds are l-diazo-4-(N,N-diethylamino) Citric acid 2,0 g benzene fluoroborate, l-diazo-2-ethoxy-4-(N,N- Resorcinol 0.3 g diethylamino) benzene fluoroborate and l-diazo-2,5-diethox- N-(2'-methylphenyl)-2-hydroxy-3-naphthoamrde 0.5 g y 4 morpholino benzene fluroborate N--y-morpholino-n-propyl-2-hydroxy-3- naphthoamide 0.4 g 

2. A diazotype copying material as claimed in claim 1, wherein the background absorbance at 4,000 A of the light-sensitive layer does not exceed 2.0.
 3. A diazotype copying material as claimed in claim 1, wherein the support is a transparent film.
 4. A copying material as claimed in claim 1, wherein the diazonium compounds are 1-diazo-4-(N,N-diethylamino) benzene fluoroborate, 1-diazo-2-ethoxy-4-(N,N-diethylamino) benzene fluoroborate and 1-diazo-2,5-diethoxy-4-morpholino benzene fluoroborate. 